Flat sand shell
| Flat sand shell | ||||||||||||
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Flat sand mussel ( Gari depressa ) |
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| Scientific name | ||||||||||||
| Gari depressa | ||||||||||||
| ( Pennant , 1777) |
The flat sand mussel ( Gari depressa ) is a type of mussel from the family of sand mussels (Psammobiidae).
features
The flattened housing , which is not exactly the same, is up to 65 millimeters long. The right flap is slightly more arched than the left flap. It is oblong-ovoid in outline, the length / width ratio is about 1.8 to 1.9. The casing is noticeably unequal, the vertebrae sit in front of the center line (based on the casing length). The only slightly arched to almost straight anterior dorsal margin slopes gently towards the tightly rounded anterior end. The slightly shorter posterior dorsal edge is straight and slopes very gently towards the posterior end, which is offset by an angle. As a result, the rear end appears almost truncated at an angle. The case clearly gapes at the rear end. The dark brown ligament sits on the outside and extends from the vertebra for approximately 20% of the length of the posterior dorsal margin. Both flaps have a lock consisting of two cardinal teeth each; Lateral teeth are missing. In the right valve, the anterior cardinal tooth is wider than the posterior cardinal tooth, but both are split and two-pointed. In the left valve, however, the anterior cardinal tooth is large and split or two-pointed, while the posterior cardinal tooth is small and thin. The surface line is deeply indented, the U-shaped bay extends below the eddy. The line of the jacket bay coincides at the lower edge with about half the length with the jacket edge. The two sphincters can be clearly seen.
The shell is solid-walled. The surface shows fine concentric ridges and pits as well as very fine radial lines. The annual growth is well marked by deeper pits and very narrow growth strips. A weakly indicated back extends from the vertebra to the rear, lower corner (transition from the rear to the ventral edge).
The color of the shell (inside and outside) varies from glossy white, cream to yellowish. On the outside, narrow to wide, reddish brown, pink or purple bands from the vertebra extend radially towards the edge of the case. The light brown to dark brown periostracum is comparatively thick, but is still mostly abraded except for the edges of the case. The inside edge of the housing is smooth. The inside is glossy white, often yellowish with a purple or bluish tinge. The colored radial bands on the outside are hinted at on the inside.
The soft body is yellowish-whitish. The edges of the coat are slightly fringed. The animals have a large foot and two very long, separate siphons .
Geographical distribution and habitat
The range of the species stretches from the Faroe Islands southwards over the waters of the British Isles , the coasts of the Eastern Atlantic southwards to Angola . It has also been found in the waters around the Canary Islands , Madeira and the Azores . It is also found in the Mediterranean .
The representatives of the species live buried in muddy sand and gravel from a few meters below the low water line to about 150 meters water depth. The deepest find of this kind, however, was recovered from a depth of 1179 meters. Overall, the animals are rare.
Taxonomy
Thomas Pennant described the species as Tellina depressa in 1777 . It is now generally placed in the genus Gari Schumacher, 1817. In the older literature it can also be found under the younger synonym Psammobia vespertina (Gmelin, 1791). There are a number of other synonyms for this species.
supporting documents
literature
- Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 pages, Gustav Fischer Verlag, Stuttgart 1969
- Guido Poppe. Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3-925919-10-4 (p. 114)
- Paul Chambers (with figures from George Sowerby): British Seashells: A Guide for Collectors and Beachcombers. 233 pp., Remember When, Barnsley Yorkshire, 2009 ISBN 978-1-84468-051-1 Preview on Google Books (p. 172)
On-line
Individual evidence
- ^ Theodor CH Cole: Dictionary of Invertebrates / Dictionary of Invertebrates: Latin-German-English. Springer Spektrum, Berlin 2017, ISBN 978-3-662-52869-3 , p. 64. Preview on Google Books
- ^ Thomas Pennant: British Zoology. Vol. IV. Crustacea. Mollusca. Testacea. Pp. III-VIII, 1-154, Plates I-XCII (= 1-93), London, White, 1777 Online at www.biodiversitylibrary.org (p. 87)
- ↑ a b MolluscaBase: Gari depressa (Pennant, 1777)
